Bleaching/highlighting composition containing calcium salts

ABSTRACT

The present invention relates to bleaching composition for keratin fibres, especially human hair, comprising at least one compound with bleaching and/or highlighting effect and a calcium salt. Further object of the present invention is the use of at least one calcium salt in a bleaching and/or highlighting composition for keratin fibres, especially for human hair, comprising at least one compound with bleaching and/or highlighting effect for preventing temperature increase going above 40° C., preferably above 45° C. and more preferably above 50° C. in a period of at least 60 min after mixing water free bleaching and/or highlighting composition and oxidizing lotion.

This application is a 371 application of PCT/EP2009/001459 filed Mar. 2,2009, which claims priority to the EP application 08003950.6 filed Mar.4, 2008.

The present invention relates to bleaching composition for keratinfibres, especially human hair, comprising at least one compound withbleaching and/or highlighting effect and a calcium salt.

Hair bleaching is a common practice for ages. It is based on oxidativedecomposition of hair colour, which is usually done using peroxide orperoxide releasing compounds such as persulfates. Due to highlyirritating potential of these bleaching ingredients and dustiness ofpowder compositions, it is preferred to provide granular compositionwhere dust is reduced by agglomerating small particles into granulatesusing various binding agents. Most popular binding agent is mineral oil,which was the subject matter of EP 560 088 B1. Furthermore, EP 778 020A1 suggests the use of oil and wax compounds or their mixtures forpreparation of suspensions.

The bleaching of human hair customarily consists of a process with thefollowing steps: Homogenous mixing of a water-free preparation,preferably a powder, comprising at least one compound with a bleachingand/or highlighting effect, in particular a solid peroxide salt,preferably ammonium, potassium and/or sodium persulfate or earth alkaliperoxide, with an aqueous hydrogen peroxide composition, application ofthis composition onto the hair, and rinsing after bleaching iscompleted. It has been known for some time that use of these compoundsis effective with regard to the bleaching, but higher concentrations canlead to hair damage and/or scalp irritation. In some cases, it hasfurther been observed that during mixing of the above mentioned twocompositions and/or processing on the hair after application of themixture, excessive heat develops which results in excessive hair damageand extreme scalp irritations and more seriously scalp burning. It wasfound out that in some cases temperature on the hair and scalp raiseseasily to approximately 80° C. Prevention of said excessive heatdevelopment will help very much to a safe and milder beaching process.

The source of the excessive heat development can be any reaction takingplace within the mixture of aqueous oxidizing and water free bleachingcompositions. Without being bound by the theory, it has been thoughtthat heavy metal ion contaminations can be responsible for extreme andsteady increase in the temperature of the mixture either during mixingor during processing on keratin fibre especially hair. Heavy metal ionsmay be introduced to the mixture by non-optimal working conditions suchas using improperly cleaned utensils and also by the use of contaminatedwater for cleaning the equipment used for mixing and applying bleachingcomposition onto hair. Another source may be deposition of heavy metalson or into hair from the environment.

In order to test the above theory, cupper chloride was added into themixture of bleaching powder and oxidizing lotion and the temperature ofthe mixture was observed for a period of 60 min. It was found out thatat the beginning temperature increase is rather slow but after a periodof 15 min a rapid increase was found. The highest temperature reachedwas approximately 75° C. (FIG. 1)

Therefore, aim of the present invention is to find out a composition forbleaching and/or highlighting hair with which such excessive heatdevelopment does not take place.

The inventors of the present invention have surprisingly found out thatexcessive heat development does not take place when a calcium salt (seebelow for the specific calcium salts referred to) is used in water freebleaching composition which is than mixed with an oxidizing composition.

Use of various calcium salts is know from a Japanese patent publicationJP 2003-206221 A1 for enhancing bleaching effect. In the documentcalcium chloride, iodide and bromide salts have been mentioned. Thedocument does not address excessive heat development and/or preventionof it.

The first object of the present invention is a water free bleachingand/or highlighting composition for keratin fibres, especially humanhair, comprising at least one compound with bleaching and/orhighlighting effect and at least one calcium salt selected from calciumaluminium borosilicate, calcium aspartate, calcium benzoate, calciumacetate, calcium carbonate, calcium citrate, calcium dihydrogenphosphate, calcium fluoride, calcium hydroxide, calcium lactate, calciummonofluorophosphate, calcium oxide, calcium phosphate, calciumpropionate, calcium pyrophosphate, calcium sulphate, calcium nitrate,calcium salicylate, calcium silicate, hydrate, calcium tartarate,tricalcium phosphate.

The second object of the present invention is the use of at least onecalcium salt in a bleaching composition for keratin fibres, especiallyfor human hair, comprising at least one compound with bleaching and/orhighlighting effect for preventing excessive heat development.

The third object of the present invention is the use of at least onecalcium salt in a bleaching and/or highlighting composition for keratinfibres, especially for human hair, comprising at least one compound withbleaching and/or highlighting effect for preventing temperature increasegoing above 40° C., preferably above 45° C. and more preferably above50° C. in a period of at least 60 min after mixing water free bleachingand/or highlighting composition and oxidizing lotion.

With the term “excessive heat development” it is meant that thetemperature of the bleaching composition is being above 40° C.,preferably above 45° C., more preferably above 50° C. after mixing waterfree composition comprising at least compound with bleaching and/orhighlighting effect and at least one calcium salt referred above and acomposition comprising at least one oxidizing agent at a time within60min.

The term bleaching composition is used to define any bleachingcomposition either water free or an aqueous i.e. after mixing withaqueous oxidizing agent.

With the term “water free bleaching and/or highlighting composition” itis meant that no additional water is introduced into the compositionother than bound water to the ingredients which may be as high as 1% ofthe composition.

Bleaching and/or highlighting compositions of the present inventioncomprises at least one calcium salt. Both organic and inorganic ones aresuitable for the purpose of the present invention. Inorganic salts aremost preferred. Suitable calcium salts are calcium aluminiumborosilicate, calcium aspartate, calcium benzoate, calcium acetate,calcium carbonate, calcium citrate, calcium dihydrogen phosphate,calcium fluoride, calcium hydroxide, calcium lactate, calciummonofluorophosphate, calcium oxide, calcium phosphate, calciumpropionate, calcium pyrophosphate, calcium sulphate, calcium nitrate,calcium salicylate, calcium silicate, hydrate, calcium tartarate,tricalcium phosphate, calcium chloride, calcium iodide and calciumbromide. Preferred are calcium benzoate, calcium acetate, calciumcarbonate, calcium citrate, calcium dihydrogen phosphate, calciumfluoride, calcium hydroxide, calcium lactate, calciummonofluorophosphate, calcium oxide, calcium phosphate, calciumpropionate, calcium pyrophosphate, calcium sulphate, calcium nitrate,calcium salicylate, calcium silicate, hydrate, calcium tartarate,tricalcium phosphate, calcium chloride, calcium iodide and calciumbromide. More preferred calcium acetate, calcium carbonate, calciumcitrate, calcium dihydrogen phosphate, calcium fluoride, calciumhydroxide, calcium lactate, calcium oxide, calcium phosphate, calciumpropionate, calcium pyrophosphate, calcium sulphate, calcium nitrate,calcium silicate, calcium tartarate, calcium chloride, calcium iodideand calcium bromide. The most preferred are calcium carbonate, calciumdihydrogen phosphate, calcium fluoride, calcium hydroxide, calciumoxide, calcium phosphate, calcium pyrophosphate, calcium sulphate,calcium nitrate, calcium chloride, calcium iodide and calcium bromide.Calcium sulphate is particularly preferred because of its outstandingeffect.

Concerning the above mentioned list of calcium salts it should be notedthat calcium chloride, calcium iodide and calcium bromide are insertedinto the list because of their use for preventing the excessive heatdevelopment because Japanese patent publication mentioned abovediscloses the three calcium salt in a bleaching composition.

Concentration of at least one calcium salt in the compositions of thepresent invention is between 0.1 and 20%, preferably between 0.5 and15%, more preferably between 0.75 and 10% and most preferably between 1and 7.5% by weight calculated to total composition prior to mixing withoxidizing lotion.

According to the present invention, the composition comprises at leastone compound with bleaching and/or highlighting effect. Suitablecompounds are in general peroxides. Useful as such are in particularpersulfates such as sodium and potassium persulfate, ammoniumpersulfate, earth alkali peroxides such as magnesium peroxide, melamineperoxide or urea peroxide or phtholimidoperoxy-hexanoic acid, andmixtures thereof. The proportion of peroxides is at least 5%, preferablyin the range of 20 to 80%, more preferably 25 to 60% and most preferably30 to 55% by weight, calculated to total composition prior to mixingwith oxidizing lotion.

According to the invention, the water free composition can also comprise0.1% to 10% by weight, calculated to total composition prior to mixingwith oxidizing lotion, at least one ammonium salts. Suitable ammoniumsalts are ammonium carbonate, ammonium hydrogen carbonate, ammoniumcarbamate, ammonium chloride, ammonium sulfate, ammonium phosphates,ammonium nitrate, ammonium bromide, ammonium iodide, ammoniumthiosulfate, ammonium molybdate, ammonium vanadate, ammonium sulfamate,ammonium citrate, ammonium salicylate, ammonium valerate, ammoniumtartarate, ammonium benzoate, ammonium acetate, ammonium formiate andammonium lactate. Compositions may also comprise mixture or ammoniumsalts.

Preferred thereof are the ammonium phosphates, such as ammoniumdihydrogen phosphate, ammonium hydrogen phosphate, diammonium sodiumphosphate, sodium ammonium hydrogen phospahe, ammonium disodiumphosphate, as well as ammonium chloride, ammonium sulphate, diammoniumhydrogen citrate, ammonium carbonate, ammonium hydrogen carbonatepreferably in an amount from 0.1% to 10% by weight, calculated to totalcomposition prior to mixing with oxidizing lotion.

As known from EP 609 796 A2, the ammonium compounds can also be used assole bleaching agent in respectively higher amounts.

The total proportion of the compounds with bleaching and/or highlightingeffect preferably ranges from 5% to 85%, preferably 20% to 80%, morepreferably 25 to 70% and most preferably 30 to 60% by weight calculatedto total composition prior to mixing with oxidizing lotion.

In addition to the active component, water free bleaching and/orhighlighting compositions also comprise the components customarily usedin such compositions: In particular inert pulverulent carrier materials,these are for example, pyrogenic silicium dioxide, starch powder, etc.,alkalizing agents, such as sodium metasilicate, surface-activesubstances, binding agents, etc. In order to avoid repetition, referenceis made to the respective standard literature, for example, K. Schraderand A. Domsch, “Cosmetology—Theory and Practice (2005, Verlag furChemische Industrie), pages 142 to 151.

In a preferred embodiment of the present invention, water free bleachingand highlighting composition of the present invention is in powder formand in particular in dust free powder form and comprises oily lipophilicingredients such as vegetable oils, for example, jojoba oil or anyother; petrolatum liquid paraffins, especially paraffinum perliquidumand parafiinum subliquidum; silicone oils; hydropobic fatty acid esterssuch as octyl palmitate, isocetyl palmitate, isopropyl palmitate andoctyl stearate, C₁₀- to C₃₆-fatty acid triglycerides, as well as theirmixtures. In the case that the use is wished among those the mostpreferred ones are silicone oils, jojoba oil, fatty acid esters,paraffin oils, combinations of fatty acid esters and paraffin oils.Fatty acid esters and/or paraffin oils and/or silicone oils areparticularly preferred. Concentration of these oily lipophilic compoundsare used in a total amount of about 0.1 to 50% by weight, preferablyfrom 1 to 40% by weight, and more preferably from 2 to 35% by weight,calculated to total composition prior to mixing with oxidizing lotion.

In principal any silicone oil is useful as a lipophilic compound.Preferred are dimthicones, dimethiconols and arylated silicones as alipophilic ingredient at a concentration range of 0.1 to 50%, preferably0.5 to 40% more preferably 1 to 35% and most preferably 2.5 to 30% byweight calculated to total composition prior to mixing with oxidizinglotion. Non-limiting suitable examples are dimethicones with variousviscosity available from Dow Corning under the trade name DC 200,arylated silicones such as phenyl methicone, phenyl trimethicone,diphenyl dimethicone, diphenylsiloxy phenyl trimethicone, tetramethyltetraphenyl trisiloxane, triphenyl trimethicone, tetramethly tetraphenyltrisiloxane and pentaphenyl trimethyl trisiloxane.

Further, in another preferred form of the invention water freecomposition for bleaching and/or highlighting hair comprises polymersfrom the group consisting of cellulose polymer compounds, alginate,polysaccarides and acrylic acid polymers, preferably methyl cellulosecompounds, ethyl cellulose compounds, hydroxyethylcellulose compounds,methylhydroxyethylcellulose compounds, methylhydroxypropylcellulosecompounds, carboxymethyl cellulose compounds, alginic acids, sodiumalginates, ammonium alginates, calcium alginates, gum arabic, guar gumor xanthan gum, or acrylic acid polymers with molecular weights fromabout 1,250,000 to 4,000,000, alone or in combination with each other.The polymers are used in a total amount of 0.1 to 15%, preferably from0.2 to 10%, and more preferably in an amount of from 0.5 to 7.5% byweight, calculated to total composition prior to mixing with oxidizinglotion.

Water free bleaching and/or highlighting composition can also comprisecationic polymers as conditioning and/or thickening agents. Those arecationic cellulose type polymers know as Polymer JR type from Amercholsuch as Polyquaternium 10 or cationic guar gum known with trade nameJaguar from Rhône-Poulenc and chemically for example Guar hydroxypropyltrimonium chloride. Furthermore, chitosan and chitin can also beincluded in the compositions as cationic natural polymers.

Furthermore, it has been found suitable those cationic polymers knownwith their CTFA category name Polyquaternium. Typical examples of thosePolyquaternium 1, Polyquaternium 2, Polyquaternium 4, Polyquaternium 5,Polyquaternium 6, Polyquaternium 7, Polyquaternium 8, Polyquaternium 9,Polyquaternium 10, Polyquaternium 11, Polyquaternium 12, Polyquaternium13, Polyquaternium 14, Polyquaternium 15, Polyquaternium 16,Polyquaternium 17, Polyquaternium 18, Polyquaternium 19, Polyquaternium20, Polyquaternium 22, Polyquaternium 24, Polyquaternium 27,Polyquaternium 28, Polyquaternium 29, Polyquaternium 30, Polyquaternium31, Polyquaternium 32, Polyquaternium 33, Polyquaternium 34,Polyquaternium 35 and Polyquaternium 36, Polyquaternium-37,Polyquaternium 39, Polyquaternium 42, Polyquaternium 43, Polyquaternium44, Polyquaternium 45, Polyquaternium 46, Polyquaternium 47,Polyquaternium 48, Polyquaternium-49, Polyquaternium 50, Polyquaternium51, Polyquaternium 52, Polyquaternium 53, Polyquaternium 54,Polyquaternium 55, Polyquaternium 56, Polyquaternium 57, Polyquaternium58, Polyquaternium 59, Polyquaternium 60, Polyquaternium 61,Polyquaternium 62, Polyquaternium 63, Polyquaternium 64, Polyquaternium65, Polyquaternium 66, Polyquaternium 67, Polyquaternium 68,Polyquaternium 69, Polyquaternium-70, Polyquaternium 71, Polyquaternium72, Polyquaternium 73, Polyquaternium 74, Polyquaternium 75,Polyquaternium 76, Polyquaternium 77, Polyquaternium 78,Polyquaternium-79, Polyquaternium 80, Polyquaternium 81, Polyquaternium82, Polyquaternium 83, Polyquaternium 84, Polyquaternium 85,Polyquaternium 86 and Polyquaternium 87.

As well those polymers known with their CTFA category name Quaterniumare suitable. Those are for example Quaternium-8, Quaternium-14,Quaternium-15, Quaternium-18, Quaternium-22, Quaternium-24,Quaternium-26, Quaternium-27, Quaternium-30, Quaternium-33,Quaternium-53, Quaternium-60, Quaternium-61, Quaternium-72,Quaternium-78, Quaternium-80, Quaternium-81, Quaternium-82,Quaternium-83 and Quaternium-84.

Typical concentration range for any of the cationic conditionersmentioned above can be 0.1-7.5% by weight, preferably 0.3-5% by weightand more preferably 0.5-2.5% by weight, calculated to total compositionprior to mixing with an oxidizing agent.

Water free bleaching and/or highlighting composition of the presentinvention may comprise at least one dialkyl carbonate of general formulaR₁OC(O)OR₂

where R₁ and R₂ are independent from each other linear or branchedsaturated alkyl chains with 6 to 22 C atoms.

Preferred at least one dialkyl carbonate is selected from di(caprylyl)carbonate and di(ethylhexyl) carbonate.

Concentration of at least dialkyl carbonate may vary between 0.1 and 30%by weight calculated to total composition prior to mixing with anoxidizing agent.

Water free bleaching and/or highlighting compositions of the presentinvention can comprise synthetic mica coated with metal oxide or oxideshaving a volume particle size distribution in the range of 1 to 750 μm.Use of synthetic mica coated with metal oxide or oxides mainly indecorative cosmetics is disclosed in an international patent applicationof Sun Chemical Corporation published with a number WO 2005/065632 A1.In the document synthetic mica and coated synthetic mica with at leastone metal oxide or oxides is disclosed in detail. The content of thedocument is included herewith by reference.

Suitable metal oxide or oxides for coating synthetic mica are titaniumdioxide, chromium oxide, ferric oxide or mixtures thereof. In thepresent invention the preferred is synthetic mica coated with titaniumdioxide. Such materials are commercially available from Sun ChemicalCorporation and Merck (Timiron Synwhite 40) and known with their INClnames Synthetic Fluorphologopite

The volume particle size distribution of synthetic mica coated with ametal oxide or oxides is in the range of 1 to 750 μm, preferably 1 to250 μm, more preferably 1 to 100 μm and most preferably 5 to 95 μm. Theparticle sizes referred are relating to the volume particle sizedistribution meaning that particles found in the coated synthetic micahaving volume particle size in the given ranges.

Concentration of synthetic mica coated with at least metal oxide oroxides is from 0.01 to 20%, preferably 0.1 to 15%, more preferably 0.25to 10% and most preferably 0.5 to 55% by weight calculated to totalcomposition prior to mixing with an oxidizing agent.

Interestingly, it has been observed that the mixture of water freepowder composition comprising at least one bleaching and/or highlightingagent and synthetic mica coated with at least one metal oxide or oxideswith a particle size as mentioned above and a composition comprising atleast one oxidizing agent look very homogeneous, shiny and easy to applyonto hair than a mixture which does not comprise synthetic mica.

The average particle size of the dust free bleaching powder compositionaccording to the invention is generally range below 1 mm, preferablybelow 500 μm, more preferably less than 400 μm and in particular about25 to about 100 μm, thus ensuring excellent processing capability, i.e.miscibility with an aqueous hydrogen peroxide solution prior toapplication onto human hair.

The powder composition can be produced with processes such as by mixingthe powdery ingredients first and subsequently adding lipophilicingredient(s) and by fluidized bed method. In fluidized bed method,powder ingredients are mixed in a vessel and made flowing by inlettingan air flow which may be heated (preferred when using waxy component) orcarried out at room (ambient) temperature and while the powder mixfreely “flowing” lipophilic ingredient and/or mixture with any otherliquid component is sprayed from a nozzle mounted above the powderbatch.

The bleaching and/or highlighting composition of the present inventionis mixed prior to application with an oxidizing lotion comprising atleast one oxidizing agent. The oxidizing agents suitable are hydrogenperoxide, urea peroxide, melamin peroxide or perborate salts. The mostpreferred is hydrogen peroxide. Such composition comprises 2 to 12% byweight at least one oxidizing agent preferably hydrogen peroxide and iseither a solution or in the form of an emulsion. The mixing ratio isvery much dependent on the level of bleaching effect targeted, i.e. thelevel of highlighting and/or bleaching and darkness of hair beforebleaching, and can be adjusted accordingly by hair dressers. However,generally mixing ratio is within the range of 0.5 to 4 by weight(bleaching composition to oxidizing composition), preferably in therange of 1 to 2 by weight.

The pH of the ready to use product, mixture of bleaching composition andoxidizing lotion, is in the range of 8 to 12, in particular between 9and 11.

In another preferred form of the present invention a third compositionis mixed into the mixture of water free bleaching and/or highlightingcomposition and oxidizing composition. The third composition ispreferably an aqueous composition and can be in form of a solution,thickened composition, gel, emulsion or a suspension. It may even be aproduct dispensed from a pressurised contained including any one of theabove mentioned type of preparations.

The third composition preferably comprises at least one hairconditioning compound. Hair conditioning compound is preferably selectedfrom non-ionic substances, oil or oily substances, cationic compounds.

Non-ionic conditioning agents can be polyethyleneglycol mono or di fattyacid esters having general formulaR₁CO(OCH₂CH₂)_(n)OH orR₁CO(OCH₂CH₂)_(n)OOCR₂

wherein R₁ and R₂ are independent from each other saturated, unsaturatedor branched or non-branched alkyl chain with 7 to 21 C atoms and n istypically 2-100.

Suitable cationic conditioning compounds are those carrying a quaternaryammonium group or a cationizable group and selected from cationicpolymers, cationic surfactants and quaternary ammonium or aminosilicones. Suitable cationic polymers are those of best known with theirCTFA category name Polyquaternium as disclosed above for water freebleaching and/or highlighting composition as well as those polymersknown with their CTFA category name Quaternium and disclosed above forwater free bleaching and/or highlighting composition.

The third composition and also water free bleaching composition of thepresent invention can comprise an organopolysiloxane wherein at leastone silicium atom is linked to an alkylene group having a hetero-atom,in particular a nitrogen atom, with a poly-(N-acyl alkyleneimine) unitsof the formula

wherein n is a number from 1 to 5 and R₃ is hydrogen, a C₁-C₁₂-alkyl orcycloalkyl, aralkyl or aryl group as a conditioning agent. Preferredorganopolysiloxane polymers are those of the type disclosed in EP-A 640643, in particular optionally quaternized aminoalkyl, in particularaminopropyl dimethyl polysiloxane/polyethyl oxazoline copolymers of theformula

wherein m and n each are numbers from 20 to 10,000, in particular 50 to7,000, especially 100 to 5,000, x is a number between 1 and 5,preferably 3, and y is a number from 5 to 30, R₄ is a C₁-C₁₂-alkyl oraryl group, in particular a methyl, ethyl or benzyl group, and Y⁻is ananion.

Especially suited are the organopolysiloxanes disclosed under the termsA-1, A-2 and A-3 on pages 12 to 13 of EP-A 640 643. The proportion ofgraft copolymers in the hair colouring compositions according to theinvention ranges from 0.05% to 5%, preferably 0.1% to 2.5%, inparticular 0.5% to 1.5% by weight, calculated to the total compositionprior to mixing with oxidizing and bleaching and/or highlightingcomposition.

Cationic surfactants suitable for the third composition of the presentinvention are according to the general formula

where R₅ is a saturated or unsaturated, branched or straight alkyl chainwith 8-22 C atoms orR₉CONH(CH₂)_(n)

where R₉ is saturated or unsaturated, branched or straight alkyl chainwith 7-21 C atoms and n has value of 1-4,

orR₁₀COO(CH₂)_(n)

where R₁₀ is saturated or unsaturated, branched or straight alkyl chainwith 7-21 C atoms and n has value of 1-4, and

R₆ is hydrogen or unsaturated or saturated, branched or straight alkylchain with 1-22 C atoms orR₉CONH(CH₂)_(n)orR₁₀COO(CH₂)_(n)

where R₉, R₁₀ and n are same as above.

R₇ and R₈ are hydrogen or lower alkyl chain with 1 to 4 carbon atoms,and X is anion such as chloride, bromide, methosulfate.

Typical examples of those ingredients are cetyltrimethyl ammoniumchloride, steartrimonium chloride, behentrimonium chloride,stearamidopropyl trimonuim chloride, dioleoylethyl dimethyl ammoniummethosulfate, dioleoylethyl hydroxyethylmonium methosulfate.

Amido amines may as well be used as a conditioning cationic surfactantin the compositions of the present invention. Typical non-limitingexample is stearamidopropylamine known with a trade name Tego Amid S18from Degussa and behenamidopropyl dimethyl amine available under thetrade name Amidet APA 22 from Kao Chemicals.

Oily substances are selected from such as silicone oils, volatile ornon-volatile, natural and synthetic oils. Among silicone oils those canbe added to the compositions include dimethicone, dimethiconol,polydimethylsiloxane, DC fluid ranges from Dow Corning, arylatedsilicones such as phenyl trimethicone or any other silicone with up to 5aryl, preferably phenyl, group in its molecule, natural oils such asolive oil, almond oil, avocado oil, wheatgerm oil, ricinus oil and thesynthetic oils, such as mineral oil, isopropyl myristate, palmitate,stearate and isostearate, oleyl oleate, isocetyl stearate, hexyllaurate, dibutyl adipate, dioctyl adipate, myristyl myristate and oleylerucate.

The compositions according to the invention may also comprise furtherconditioning substances such as protein hydrolyzates and polypeptides,e.g., keratin hydrolyzates, collagen hydrolyzates of the type“Nutrilan^(R)” or elastin hydrolyzates, as well as also in particularplant protein hydrolyzates, optionally, cationized protein hydrolyzates,e.g., “Gluadin^(R)”.

Typical concentration range for any of those conditioners, non-ioniccompounds, oil or oil like substances, cationic polymers, silicon oiland derivatives and cationic surfactants is in the range of 0.01-10% byweight, preferably 0.01-7.5% by weight, more preferably 0.05-5% and mostpreferably 0.1-5% by weight calculated to the total composition prior tomixing with oxidizing and bleaching and/or highlighting composition.

In the case that the third composition is in the form of an emulsion, itcomprises as an emulsion base at least one fatty alcohol or mixture offatty alcohols with the chain length of 14 to 22 C atoms. Examples tosuitable fatty alcohols, without limiting the choice, are myristylalcohol, cetyl alcohol, stearyl alcohol, behenyl alcohol and cetostearylalcohol. The most preferred is cetostearyl alcohol well known with itstrade name Lanette O or as Lanette N in mixture with sodium cetearylsulfate from Cognis.

The concentration of fatty alcohol(s) is in the range from 0.5 to 20%,preferably 1 to 15% by weight, calculated to total composition prior tomixing with oxidizing and bleaching and/or highlighting composition.

The third composition according to present invention comprisessurfactants selected from anionic, nonionic, amphoteric (or zwiterionic)and/or cationic surfactants or their mixtures as emulsifier orsolubilizer. Cationic surfactants are as well used as hair conditionersas mentioned above.

Anionic surfactants suitable within the scope of the invention are inprincipal known from the cleansing compositions

These are anionic surfactants of the sulfate, sulfonate, carboxylate andalkyl phosphate type, for example, the known C₁₀-C₁₈-alkyl sulfates, andin particular the respective ether sulfates, for example, C₁₂₋C₁₄-alkylether sulfate, lauryl ether sulfate, especially with 1 to 4 ethyleneoxide groups in the molecule, monoglyceride (ether) sulfates, fatty acidamide sulfates obtained by ethoxylation and subsequent sulfatation offatty acid alkanolamides, and the alkali salts thereof, as well as thesalts of long-chain mono- and dialkyl phosphates.

Additional anionic surfactants useful within the scope of the inventionare α-olefin sulfonates or the salts thereof, and in particular alkalisalts of sulfosuccinic acid semiesters, for example, the disodium saltof monooctyl sulfosuccinate and alkali salts of long-chain monoalkylethoxysulfosuccinates.

Suitable surfactants of the carboxylate type are alkyl polyethercarboxylic acids and the salts thereof as well as alkyl amido polyethercarboxylic acids and salts thereof. Such products have been known forsome time and are on the market, for example, under the trade name“AKYPO®” and “AKYPO-SOFT®”.

Further suitable anionic surfactants are also C₈-C₂₂-acylaminocarboxylic acids or the water-soluble salts thereof. Especiallypreferred is N-lauroyl glutamate, in particular as sodium salt, as wellas, for example, N-lauroyl sarcosinate, N—C₁₂-C₁₈-acyl asparaginic acid,N-myristoyl sarcosinate, N-oleoyl sarcosinate, N-lauroyl methylalanine,N-lauroyl lysine and N-lauroyl aminopropyl glycine, preferably in formof the water-soluble alkali or ammonium, in particular the sodium saltsthereof, preferably in admixture with the above-named anionicsurfactants.

It is also possible to use mixtures of several anionic surfactants.

Further surfactants in the third composition according to the inventionare nonionic surfactants which are one of the preferred emulsifyingsurfactant within the scope of present invention. Especially suitednonionic surfactants are, for example, long-chain fatty acid mono- anddialkanolamides, such as coco fatty acid mono- or diethanolamide andmyristic fatty acid mono or diethanolamide, stearic acid mono ordiethanolamide. Further nonionic surfactants suited are alkylpolyglucosides with an alkyl group of 8 to 18 carbon atoms, and with 1to 5 glucoside units. Further additionally useful nonionic surfactantsare, for example, the various sorbitan esters, such as polyethyleneglycol sorbitan stearic acid ester, fatty acid polyglycol esters orpoly-condensates of ethyleneoxide and propyleneoxide, as they are on themarket, for example, under the trade name “Pluronics^(R)”, as well asfatty alcohol ethoxylates. Further nonionic surfactants preferred in thedyeing compositions according to invention are C₁₀-C₂₂-fatty alcoholethoxylates. Especially suited are C₁₀-C₂₂-fatty alcohol ethers, thealkyl polyglycol ethers known by the generic terms “Laureth”,“Myristeth”, “Oleth”, “Ceteth”, “Deceth”, “Steareth” and “Ceteareth”according to the CTFA nomenclature, including addition of the number ofethylene oxide molecules, e.g., “Laureth-16”: The average degree ofethoxylation thereby ranges between about 2.5 and about 25, preferablyabout 10 and about 20.

As further surfactant component, the dyeing compositions according tothe invention can also contain amphoteric or zwitterionic surfactants.Useful as such are in particular the various known betaines such asalkyl betaines, fatty acid amidoalkyl betaines and sulfobetaines, forexample, lauryl hydroxysulfobetaine; long-chain alkyl amino acids, suchas cocoaminoacetate, cocoaminopropionate and sodium cocoamphopropionateand -acetate have also proven suitable.

Cationic surfactants mentioned above as conditioner and especially thosewith single long alkyl chain such as cetrimonium chloride andbehentrimonium chloride are also suitable emulsifiers according topresent invention.

The concentration of one or more emulsifiers in the third compositionsis in the range from 0.1 to 15%, preferably 0.5 to 10% by weight,calculated to total composition prior to mixing with oxidizing andbleaching and/or highlighting composition.

The third composition according to the present invention can containorganic solvent. Examples of such organic solvents are benzyloxyethanol, benzyl alcohol, phenoxy ethanol, phenoxy isopropanol, methylphenoxy ethanol, benzyl glycerol, N-benzyl formide, N-methylpyrrolidone, N-ethyl pyrrolidone, cinnamyl alcohol, phenethyl alcohol,p-methyl benzyl alcohol, butyl cellosolve, methyl carbitol, ethylcarbitol, propyl carbitol, butyl carbitol, diethyleneglycol, diethylether and dipropyleneglycol diethyl ether. Typically the concentrationof those solvents can be in the range from 0.5% to 10%, preferably0.5-5% by weight calculated to the total composition prior to mixingwith oxidizing and bleaching and/or highlighting composition.

The third composition can contain one or more thickening agents. Thethickening agents disclosed for water free bleaching and/or highlightingcompositions are also suitable for the third composition at the abovegiven concentration ranges.

Another preferred compound in the composition of present inventionespecially in bleaching and/or highlighting composition and in the thirdcomposition is ceramide type of compounds according to general formula

wherein R₁₁ and R₁₂ are independent from each other alkyl- or. alkenylgroup with 10 to 22 carbon atoms, R₁₃ is alkyl or hydroxyl alkyl with 1to 4 carbon atoms group and n is a number between 1 to 6, preferably 2or 3. Preferred compound according to the above chemical structure iscetyl-PG-hydroxyethylpalmitamide. Concentration of ceramide type ofcompounds ranges from 0.01 to 2%, preferably 0.01 to 1% by weightcalculated to total composition prior to mixing with oxidizing andbleaching and/or highlighting composition.

Another preferred compound in the composition of present inventionespecially in bleaching and/or highlighting composition and in the thirdcomposition is ubichinone type of compounds according to general formula

wherein n is a number from 1 to 10. Concentration of ubichinone can varybetween 0.001% and 10% by weight, calculated to the total compositionprior to mixing with oxidizing and bleaching and/or highlightingcomposition.

The third composition may as well comprise UV filters of oil soluble,non-ionic, ones and/or as well those of water soluble and mainly ofanionic character. Non-limiting examples are Benzophenone-1Benzophenone-2, Benzophenone-3, Benzophenone-7, Benzophenone-6,Benzophenone-8, octylmethoxy cinnamate, homosalat to those of oilsoluble ones and Benzophenone-4, benzophenone-9 to those anionic watersoluble ones. It should be noted that the other UV filters of oil andwater soluble ones should as well be possible to combine. Concentrationof UV filters is in the range of 0.05 to 5%, preferably 0.1 to 2.5% andmore preferably 0.1 to 1% by weight calculated to total compositionprior to mixing with oxidizing and bleaching and/or highlightingcomposition.

Conditioning agents preferred are the ones mentioned above as oilylipophilic ingredients such as natural, synthetic and mineral oils andcationic compounds such as quaternary ammonium surfactants and cationicpolymer disclosed above as well.

According to the preferred embodiment of the present invention, the thircomposition comprises at least one direct dye. Suitable direct dyes areanionic, cationic and non-ionic nitro dyes.

Suitable anionic direct dyes in aqueous composition are Acid Black 1,Acid Blue 1, Acid Blue 3, Food Blue 5, Acid Blue 7, Acid Blue 9, AcidBlue 74, Acid Orange 3, Acid Orange 6, Acid Orange 7, Acid Orange 10,Acid Red 1, Acid Red 14, Acid Red 18, Acid Red 27, Acid Red 50, Acid Red52, Acid Red 73, Acid Red 87, Acid Red 88, Acid Red 92, Acid Red 155,Acid Red 180, Acid Violet 9, Acid Violet 43, Acid Violet 49, Acid Yellow1, Acid Yellow 23, Acid Yellow 3, Food Yellow No. 8, D&C Brown No. 1,D&C Green No. 5, D&C Green No. 8, D&C Orange No. 4, D&C Orange No. 10,D&C Orange No. 11, D&C Red No. 21, D&C Red No. 27, D&C Red No. 33, D&CViolet 2, D&C Yellow No. 7, D&C Yellow No. 8, D&C Yellow No. 10, FD&CRed 2, FD&C Red 40, FD&C Red No. 4, FD&C Yellow No. 6, FD&C Blue 1, FoodBlack 1, Food Black 2, Disperse Black 9 and Disperse Violet 1 and theiralkali metal salts such as sodium, potassium. Among those, the mostpreferred anionic dyestuffs are Acid Red 52, DC Violet 2, DC Red 33, DCOrange 4, DC Red 27 and DC Yellow 10.

Suitable cationic dyes in aqueous composition are in principal thoseavailable on the market for cosmetic hair colouring applications. Forthis purpose, special reference is made to the PCT application WO95/15144 of Ciba-Geigy AG. Some examples to those are Basic Blue 6,Basic Blue 7, Basic Blue 9, Basic Blue 26, Basic Blue 41, Basic Blue 99,Basic Brown 4, Basic Brown 16, Basic Brown 17, Natural Brown 7, BasicGreen 1, Basic Red 2, Basic Red 12 Basic Red 22, Basic Red 76, BasicViolet 1, Basic Violet 2, Basic Violet 3, Basic Violet 10, Basic Violet14, Basic Yellow 57, Basic red 51, Basic Yellow 87 and Basic Orange 31.The most preferred ones are Basic red 51, Basic Yellow 87 and BasicOrange 31 sold by CIBA.

Additionally, the aqueous compositions of the present invention maycomprise neutral dyes (HC dyes), so called nitro dyes for shadingpurposes. Some examples to those are: HC Blue No.2, HC Blue No.4, HCBlue No.5, HC Blue No.6, HC Blue No.7, HC Blue No.8, HC Blue No.9, HCBlue No.10, HC Blue No.11, HC Blue No.12, HC Blue No.13, HC Brown No.1,HC Brown No.2, HC Green No.1, HC Orange No.1, HC Orange No.2, HC OrangeNo.3, HC Orange No.5, HC Red BN, HC Red No.1, HC Red No.3, HC Red No.7,HC Red No.8, HC Red No.9, HC Red No.10, HC Red No.11, HC Red No.13, HCRed No.54, HC Red No.14, HC Violet BS, HC Violet No.1, HC Violet No.2,HC Yellow No.2, HC Yellow No.4, HC Yellow No.5, HC Yellow No.6, HCYellow No.7, HC Yellow No.8, HC Yellow No.9, HC Yellow No.10, HC YellowNo.11, HC Yellow No.12, HC Yellow No.13, HC Yellow No.14, HC YellowNo.15, 2-Amino-6-chloro-4-nitrophenol, picramic acid,1,2-Diamino-4-nitrobenzol, 1,4-Diamino-2-nitrobenzol,3-Nitro-4-aminophenol, 1-Hydroxy-2-amino-3-nitrobenzol and2-hydroxyethylpicramic acid.

Plant dyestuffs can also be used alone or in combination with syntheticdirect-acting dyestuffs, for example henna (red or black), alkanna root,laccaic acid, indigo, logwood powder, madder root and rhubarb powder,etc.

From the above disclosed direct dyes the preferred are cationic andnitro dyes and most preferred are cationic direct dyes.

According to the invention, the third composition comprises one or moredirect dye at a concentration of 0.1 to 7.5% by weight calculated to thetotal composition prior to mixing with bleaching and oxidizingcompositions mentioned above. The third composition can also comprisemixture of several direct dyes i.e. an anionic, a cationic and/or anonionic ones. In such a case the dyes may be mixed at any ratio witheach other.

The above mentioned direct dyes of cationic, anionic and nonioniccharacter can also be added into the water free bleaching and/orhighlighting composition at the concentration given in the aboveparagraph. The direct dyes of different characters can certainly bemixed as well.

pH of the aqueous third composition of the present invention variesbetween 2 and 12, preferably 3-10, more preferably 4 to 8. pH isadjusted to the required pH by using monoethanolamine, triethanolamine,ammonia or its salts with acids such as ammonium chloride, ammoniumsulphate, ammonium carbonate, ammonium bicarbonate, ammonium nitrate, orusing alkaline solutions such as sodium hydroxide, potassium hydroxideand their respective salts with the known acids.

It should be noted that pH of the mixture of bleaching and/orhighlighting composition, third composition and oxidizing lotion, readyto use composition, is in the range of 8 to 12, in particular between 9and 11.

The mixing ratio of the bleaching and/or highlighting composition tothird composition, depending on the colour result to be achieved variesbetween 10:1 to 1:1, preferably 8:1 to 2:1 and more preferably 5:1 to3:1, all by weight, which may further mixed with an oxidizing lotion ata weight ratio of preferably 1:1. The above ratios are valid when thirdcomposition does not comprise direct dye. In case direct dye iscontained in the third composition preferred mixing ratio is 1:1 whichthan mixed with oxidizing lotion.

Accordingly, further object of the present invention is a kit forbleaching and/or highlighting keratin fibres especially human haircomprising

a—a water free composition comprising at least one compound withbleaching and/or highlighting effect and at least one calcium salt

b—an aqueous composition comprising at least one oxidizing agent

c—a third composition preferably an aqueous composition comprising atleast one hair conditioning agent and/or a direct dye.

Further object of the present invention use of at least one calcium saltfor preventing temperature increase above 40° C. preferably above 45° C.and more preferably 50° C. in a product in kit form comprising

a—a water free composition comprising at least one compound withbleaching and/or highlighting effect

b—an aqueous composition comprising at least one oxidizing agent

c—a third composition preferably an aqueous composition comprising atleast one hair conditioning agent

wherein calcium salt is preferably comprised in water free bleachingand/or highlighting composition.

Hair bleaching process is carried out as usual using the compositions ofthe present invention. Briefly, the mixture of water free composition,oxidizing lotion and optionally third compositions is prepared andapplied onto dry hair and processed for 5 to 45 min and rinsed of fromhair and shampooed, if necessary.

Although the preferred process for dyeing and bleaching is a single stepprocess, two-step processes may as well be used with the compositions ofthe present invention.

One of the ways of carrying out in two steps is that in the first step,bleaching and/or highlighting composition of the present invention isfirstly mixed with an oxidizing agent and applied onto hair and left 5to 20 min and afterwards without rinsing off the third compositioncomprising at least one direct dye is applied onto hair and additionallyprocessed for 5 to 30 min and rinsed off from hair and shampooed, ifnecessary.

In another way of carrying out the invention in two step is that in thefirst step, bleaching and/or highlighting composition of the presentinvention is firstly mixed with an oxidizing agent and applied onto hairand left 5 to 45 min and afterwards rinsed off from hair andsubsequently in the second step dyeing composition is applied onto hairand additionally processed for 5 to 45 min and rinsed off from hair andshampooed, if necessary.

The composition of the present invention can contain additionalingredients such as preservatives, chelating agents, fragrance andsubstances customarily used in cosmetic bleaching and colouringcompositions of keratin fibres, especially hair.

The invention is illustrated with the following examples, but notlimited to.

EXAMPLE 1

Water Free Bleaching and/or Highlighting Compositions

Potassium persulfate 40 by weight Sodium persulfate 5 Sodium carbonate 1Sodium silicate 10 Diatomaceous Earth 40 Calcium sulfate 4

The above composition is prepared by combining all powder componentstogether and by mixing until homogeneity in a suitable mixer.

In order to test the excessive heat development preventing effect ofcalcium salt, in the example calcium sulphate, a comparative compositionis prepared without 4% by weight calcium salt. In this case DiatomaceousEarth concentration is increased to 44% by weight. Both compositionswere spiked with copper chloride at a concentration of 0.048 g per 100 gbleaching composition after mixing with oxidizing lotion below.

The water free bleaching compositions were mixed with an oxidizingcomposition of the following composition at a weight ratio of water freepowder to oxidizing lotion 1:2.

Oxidizing Lotion

Hydrogen peroxide 9.00 (% by wt.) Cetyl stearyl alcohol 1.70 Phosphoricacid 0.50 Sodium lauryl sulfate 0.20 Coenzyme Q10 0.05 Cetyl PGhydroxyethyl palmitamide 0.10 Disodium hydrogen phosphate 0.10 Salicylicacid 0.10 Water ad 100.00

The temperature of the mixture was followed for 60 min with a digitalthermometer and recorded in regular distances. The results are presentedin FIG. 1.

FIG. 1: Temperature changes of bleaching compositions

As clearly shown in FIG. 1 temperature of the composition withoutcalcium sulphate increases to approximately 75° C. but temperature ofthe composition with calcium sulphate does not increase more thanapproximately 30° C. This results show clearly that in the presence ofcalcium chloride excessive heat development in bleaching compositions isprevented by the presence of calcium salt, in this particular example bythe presence of calcium sulphate.

Similar results were observed with the following examples

EXAMPLE 2

Bleaching/Highlighting Powder Composition

Hydroxyethylcellulose  1.00% by weight Cellulose gum  3.00 TetrasodiumEDTA  2.00 Sodium carbonate  1.00 Ammonium persulfate 21.00 Potassiumpersulfate 46.60 Sodium metasilicate 10.00 Diatomaceous Earth 11.00Polyquaternium - 10  0.50 Calcium chloride  3.00

The above composition was tested in a half side test for its performanceon bleaching with 10 volunteers having shoulder length hair. As acomparative composition a composition without calcium chloride but with14% by weight diatomaceous earth was prepared. Bleaching composition wasprepared by mixing above water free composition with oxidizing lotion ofexample 1 at a weight ratio of 1:2 (powder to lotion). Approximately 30g of each was applied onto hair and processed for 30 min at ambienttemperature. Afterwards bleaching composition was rinsed off from hairand shampooed ones and dried with a hair drier.

It was observed that the half side bleached with a composition accordingto present invention was better in combing, softer and had more shine.Volunteers were of the opinion that it was more natural upon touchingthan the half side bleached with comparative composition.

In a further test, temperature of both compositions was observed afterspiking with copper chloride at a concentration of 0.048 g per 100 gbleaching composition. It was observed that the temperature of thecomparative composition was reached approximately 83° C. whereas thetemperature of the inventive compositions did not go beyond 32° C.

EXAMPLE 3

Bleaching and colouring in a single process was carried our using thebleaching composition of example 1, dyeing composition according to thecomposition below and an oxidizing lotion composition of example 1,however with 6% hydrogen peroxide content instead of 9%.

The Third Composition with Dyestuff

% by weight Cocamide MEA 4.00 Cetearyl alcohol 10.00 Tegin P 1.40Propylene Glycol 2.40 Oleic acid 3.00 Coenzyme Q10 0.10 Ammoniumchloride 0.50 Tetrasodium EDTA 0.20 Sodium lauryl sulfate 1.50Polysilicone-9 0.20 Pentaphenyl trimethyl trisiloxane 5.00 Cetyl PGhydroxyethyl palmitamide 0.10 Basic red 51 0.50 Water to 100

The bleaching composition of example 2, dyeing composition of above andoxidizing lotion of example 1 were mixed at a weight ratio of 1:1:1 andwas applied onto parts of hair (streak) and left 30 min at 40° C. andrinsed off with water and shampooed. Intensive highlighted red streakswere obtained.

Similar results were observed when other cationic, anionic and/ornonionic nitro dyes mentioned in the description are used instead of thecationic dye in the example.

EXAMPLE 4

The Third Composition

Cetrimonium chloride 1.0 Hydroxyethylcellulose 1.0 Cetearyl alcohol 5.0Hydrolysed silk 1.0 Fragrance q.s. Preservative q.s. Citric acid q.s. topH 5.0 Water to 100

Water free bleaching composition of example 2 is mixed with abovecomposition and with oxidizing lotion of example 1 at a weight ratio of1:1.9:0.1 (water free composition: oxidizing lotion: the thirdcomposition). The resulting composition was tested against a bleachingcomposition of Example 2. It was observed that the half side bleachedwith a composition mixed with third composition is much more caredinterms of combability, shine and softness.

EXAMPLE 5

Bleaching/Highlighting Powder Composition

Hydroxyethylcellulose  1.40% by weight Cellulose gum  3.20 Xanthan gum 0.30 Tetrasodium EDTA  2.00 Sodium carbonate  1.00 Ammonium persulfate21.00 Potassium persulfate 46.60 Sodium metasilicate 10.20 Corn starch 1.10 Diatomaceous Earth  9.30 Calcium sulphate  2.80 Polyquaternium -10  0.10 Silica*  1.00 Synthetic fluorphologopite**  1.00 *Aerosil 380**Synthetic fluorphologopite used is commercially available from Merckwith a particle size distribution in the range of 5 to 45 μm.

The above composition was produced in the same way as in example 1 andalso used in the same way as described under Example 1. Similar resultswere obtained in the temperature test. When tested against a compositionwithout calcium sulphate it was found our hair felt less damaged upontouching which was supported by better combability, better shine andsofter feel.

The invention claimed is:
 1. A method for preventing excessive heatdevelopment during bleaching and/or highlighting of keratin fibers,comprising the steps of: incorporating 0.1 to 20% by weight, calculatedto the total composition prior to mixing, of at least one calcium saltin a bleaching and/or highlighting composition, and applying saidcomposition to the keratin fibers to achieve bleaching and/orhighlighting without excessive heat development, wherein the bleachingand/or highlighting composition comprised between 30 to 80 wt. %,calculated to the total composition, of a persulfate compound, andwherein the bleaching composition is water-free and in powder form. 2.The method of claim 1, further comprising mixing the bleaching and/orhighlighting composition with an oxidizing composition, whereby thetemperature does not increase above 40° C. in a period of at least 60min after said mixing.
 3. The method according to claim 1, wherein atleast one calcium salt is selected from a group consisting of calciumaluminium borosilicate, calcium aspartate, calcium benzoate, calciumacetate, calcium carbonate, calcium citrate, calcium dihydrogenphosphate, calcium fluoride, calcium hydroxide, calcium lactate, calciummonofluorophosphate, calcium oxide, calcium phosphate, calciumpropionate, calcium pyrophosphate, calcium sulphate, calcium nitrate,calcium salicylate, calcium silicate, hydrate, calcium tartarate,tricalcium phosphate, calcium chloride, calcium iodide and calciumbromide.
 4. The method according to claim 2, wherein the compositioncomprises at least one compound with bleaching effect at a concentrationof 5% by weight, calculated to total composition prior to mixing withoxidizing composition.
 5. The method according to claim 2, wherein thecomposition comprises at least one ammonium salt.
 6. The methodaccording to claim 2, wherein the composition comprises silicone oiland/or mineral oil and/or natural oil as lipophilic ingredient.
 7. Themethod according to claim 2, wherein the composition comprises polymer.8. The method according to claim 2, wherein the composition comprisesadditionally at least one lipophilic ingredient at a concentration of 1to 50% by weight calculated to total composition prior to mixing withoxidizing lotion.
 9. The method according to claim 1, wherein thecomposition comprises additionally at least one lipophilic ingredient ata concentration of 1 to 50% by weight calculated to total compositionprior to mixing with oxidizing lotion.
 10. The method according to claim1 wherein the bleaching composition comprises between 40 to 70 wt. %,calculated to the total composition, of a persulfate compound.
 11. Themethod according to claim 1 wherein the persulfate compound is selectedfrom the group consisting of sodium persulfate, potassium persulfate andammonium persulfate.
 12. The method according to claim 11 wherein thepersulfate compound is potassium persulfate.